Bug#1026310: vdr-dev: dh_vdrplugin_depends fail with "error: Bug in helper:"

[Niels Thykier]

Control: severity -1 serious

On Sun, 18 Dec 2022 10:16:52 +0100 Christian Marillat 
<marillat at debian.org> wrote:
> Package: vdr-dev
> Version: 2.6.0-1+b1
> Severity: normal
> 
> Dear Maintainer,
> 
> I don't know if this is a bug in debhelepr or in  vdr-dev
> 
> Feel free to reassign if needed.
> 
> ,----
> | dh_vdrplugin_depends: warning: Unescaped newlines in the value of a substvars can cause broken substvars files (see #1025714).
> | dh_vdrplugin_depends: warning: Hint: If you really need a newline character, provide it as "${Newline}".
> | dh_vdrplugin_depends: error: Bug in helper: The substvar must not contain a raw newline character (vdr:Depends=vdr-abi-2.6.0-debian\n)
> `----
> 
> Christian
> 
> 
> [...]

It is a bug in `dh_vdrplugin_depends` / vdr-dev.

The package name is "vdr-abi-2.6.0-debian" without a newline in it. If 
you were to add a version to this dependency then we would have ended 
with the invalid substitution contents:

"""
vdr:Depends=vdr-abi-2.6.0-debian
(>= 2.6.0)
"""

which would have caused a parse error at dpkg-gencontrol time.  Without 
a version, you *often* get away without issues (but there are still 
cases where this could go wrong)

In the concrete case, a version is unlikely to be added (as it is 
embedded in the package name), but the newline could still cause grief 
in other cases.  Therefore, debhelper is now taking a "strict" approach 
to substvars.


Thanks,
~Niels